| 摘要 |
The invention concerns a method for preparing polyorganosiloxanes (POS) by (a) condensation polymerisation of monosilanes and/or acyclic siloxanes bearing reactive Si-OR units with R=H, or alkyl, or by (b) redistribution/condensation polymerisation of siloxane compounds based on cyclosiloxanes and/or acyclic siloxanes capable of bearing reactive Si-OR units such as defined above, Si-H or Si-alkenyl units, in the presence of an acid catalyst. Said method is characterised in that it consists in using at least a catalyst of the following formula (I) (CmF2m+1SO2)nA wherein: m is an integer not less than 1; n is an integer equal to 1 or 2 and A represents OH, NH2 or NH with: (i) n=1 and A=OH or (ii) n=1 and A=NH2 or (iii) n=2 and A=NH; provided that, when said catalyst corresponds to formula (I) (i), it is brought in the presence of an inert support in mass amount QM, expressed in weight % relative to the total mass (a) of monosilanes and/or acyclic siloxanes or (b) of the initial siloxane compounds, which is not more than 1.5. The invention also concerns a catalyst for use in the preparation of POS by said process (a) or (b) consisting of at least a compound selected among the compound of formula I(ii), the compound of formula I(iii) and mixtures thereof. |
